Motor vehicles frequently come equipped with electronic driver assistance systems that provide the driver with vehicle guidance support. What are generally referred to as ACC systems (adaptive cruise control) are known, for example, that are used for regulating the velocity of one's own vehicle. During free travel of the vehicle, when there is no vehicle in front in one's own lane, the nominal velocity is a driver-specified velocity. If, on the other hand, a vehicle driving ahead is followed, then the distance thereto is measured using a radar sensor installed in the vehicle, for example, and one's own velocity is adapted to ensure that the vehicle driving ahead is followed at an appropriate collision-avoidance distance.
While the radar sensor of the ACC system typically only monitors the space in front of the subject vehicle, sensors, such as ultrasonic sensors, or laterally and/or rearwardly directed radar sensors are also known that are able to monitor the traffic in adjacent lanes as well. As a further driver assistance function, such sensor systems then make possible what is generally referred to as blind-spot detection (BSD), thus monitoring the blind spot laterally behind the subject vehicle. This function is enhanced by what is generally referred to as a lane change assist (LCA) function, which can be used to also record the distances and relative velocities of vehicles that are located in the adjacent lane behind the subject vehicle and are coming closer to the same. On the basis of these data, a warning can then be issued, for example, in the form of a visual warning signal that is superimposed into the exterior rearview mirror of the vehicle, for instance, when it is not safe to change into the adjacent lane.
Another known driver assistance function is a lane keeping support (LKS) which issues a warning to the driver or actively intervenes in the vehicle steering when the driver is unintentionally about to leave the lane driven in so far. The warning can be a haptic signal, for example, such as a steering wheel vibration generated by the power steering. Often, a video camera having an associated image evaluation system is provided for capturing the lane markings on the roadway. This system also serves to improve the identification of the lane traveled in by the subject vehicle in the case of multilane roadways. One's own lane can, in fact, also be indirectly inferred from the radar sensor signals if there is sufficient traffic density. However, a greater accuracy is provided by the use of a video system.
What is commonly known as a multifunction camera (MFC) is often provided as a video camera. It can be utilized for other assistance functions, as well. For example, such a camera can make it easier to classify objects that had been recognized by the radar systems, but, on the basis of the radar signals, were not able to be uniquely classified as passenger cars, trucks, two-wheeled vehicles, pedestrians or the like. In the same way, the multifunction camera makes it possible to visually recognize prohibition signs, in particular speed-limit signs.
Today, motor vehicles are also typically equipped with a navigation system. It makes possible automatic route planning on the basis of a stored electronic map. Moreover, by using a satellite-based position-finding system, for example, the navigation system identifies the location of the subject vehicle and is thus able to provide the driver with navigation information. Such navigation systems usually have their own data processing system that functions independently of the remaining assistance functions. However, the navigation system can communicate via suitable interfaces with other components of the driver assistance system, which is why it is likewise to be considered here as an integral part of the vehicle's driver assistance system.